1. Field of the Invention
The present invention relates to test weights for testing the load capacity of a crane. More specifically, the present invention provides a novel system and approach for the simple and efficient load testing for a crane using solid weights.
2. Description of Related Art
Cranes are an essential component of nearly all commercial construction operations. To ensure the safety of personnel and resources at such operations, the load capacity of a crane must be pre-tested to verify that the crane is capable of lifting a particular load. Conventional methods for testing the load of a crane use a variety of weight designs and systems ranging from water weight bags to weighted platforms. In these other systems, a separate platform is required for the weights to be place upon before the crane is able to lift the system and be weight tested. With the addition of a platform component to the system, the challenge of securing the weights in place for stacking and movement of the platform is then required. Additionally, other systems require pins and hooks that a lifting device can attach a cable to in order to move the test weights into their stacked position on the platform. Finally, the required platform utilized by other systems created an overall unit that requires a greater amount of space which creates a storage issue as well as a safety issue. However all of these systems often require significant time and effort to configure a proper weight to test the crane load capacity.
One existing approach is disclosed in U.S. Pat. No. 6,725,730 entitled “Crane Test Weight Assembly and Method.” This approach uses a holder apparatus comprised of a platform with a pole or post oriented perpendicular to the platform. The weights have a centrally located hole, shaped to fit the pole or post. The weights additionally have a pair of lifting eyes disposed on exact opposite sides of the periphery of the weight. The eyes are in line with each other and this line can intersect the central axis of the opening on the weight used for placement on the post. After selecting the desired weight or plurality of weights, the weights are individually lifted and stacked into place onto the post and platform using lifting eyes and shackles or other selected rigging. Once the weights have been successfully lowered and aligned onto the platform, the crane then lifts the holder apparatus for weight testing. The system disclosed in this patent offers a method for selecting the desired amount of weight, but safety precautions demand that the weights must still be lowered onto a platform before the holder apparatus with the weights can be lifted by the crane.
Another existing approach is disclosed in U.S. Pat. No. 6,578,441 entitled “Crane Testing Apparatus and Associated Load Testing Method.” This system also uses an apparatus upon which the weights can be stacked. The weights used in this system comprise tabs on the top of the weight and holding pin openings in the bottom of the weight through which the test weight may be retained on the base of the frame. However the method for stacking the weights onto the apparatus relies upon four vertical frame posts and two intermediate beams that are used to secure the weights to the apparatus. The heavier weights are stacked on the base frame between the frame posts while the light load weights are stacked on the other sides of such frame posts. The heavier weights contain tabs on the top and holding pin openings on the bottom to secure the weights to the base frame. The lighter weights must be secured to the base frame using tie-down straps attached at their upper ends to the intermediate lift beams and at their lower ends anchored by clips to the ends of the base frame. However, this system still requires that the weights be loaded onto the base frame or platform, thereby requiring additional steps to load and align the weights on the platform and secure the plurality of weights to the platform. These additional steps require additional time and effort of the assigned personnel. Thus, a system is preferred that can eliminate these additional loading steps and maximize efficiency, while providing comparable levels of system reliability, durability, and safety.